java實現日曆的輸出

import java.text.DateFormatSymbols;
import java.util.*;

public class Test{
    public static void main(String[] args){
        GregorianCalendar d = new GregorianCalendar();

        int today = d.get(Calendar.DAY_OF_MONTH);
        int month = d.get(Calendar.MONTH);      //當前的月份應該month + 1
        System.out.println(today + " " + month);

        d.set(Calendar.DAY_OF_MONTH,1);     //獲得這個月的第一天
        int weekday = d.get(Calendar.DAY_OF_WEEK);  //獲得這個月第一天對應的星期幾
        int firstDayOfWeek = d.getFirstDayOfWeek(); //獲得當前地區星期的起始日

        //求出縮進距離
        int indent = 0;
        while(weekday != firstDayOfWeek){
            indent++;
            d.add(Calendar.DAY_OF_MONTH,-1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
        }

        String[] weekdayNmaes = new DateFormatSymbols().getShortWeekdays();
        do{
            System.out.printf("%4s",weekdayNmaes[weekday]);
            d.add(Calendar.DAY_OF_MONTH,1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
        }while(weekday != firstDayOfWeek);
        System.out.println();
        for(int i = 1;i <= indent;i++){
            System.out.printf("        ");
        }
        d.set(Calendar.DAY_OF_MONTH,1);
        do{
            int day = d.get(Calendar.DAY_OF_MONTH);
            System.out.printf("%3d",day);
            if(day == today)
                System.out.print("*   ");
            else
                System.out.print("    ");
            d.add(Calendar.DAY_OF_MONTH,1);
            weekday = d.get(Calendar.DAY_OF_WEEK);
            if(weekday == firstDayOfWeek)
                System.out.println();
        }while(d.get(Calendar.MONTH) == month);

        if(weekday != firstDayOfWeek)
            System.out.println();
    }
}